Fat cells or adipocytes are a principal storage depot for triglycerides, and are thought to be endocrine cells. Adipocytes are the only cell type known to secrete the ob gene product and adipsin, which is equivalent to Factor D of the alternative complement pathway (Zhang, Y., et al., Nature 425-432 (1994); Spiegelman, B. M., et al., J. Biol. Chem. 258:10083-9 (1983)). The ob gene product is believed to be involved in the signalling pathway from adipose tissue that acts to regulate the size of the body fat depot. Mice homozygous for a defect in the ob gene become morbidly obese (for a review see Rink, T., Nature, 372:(1994)). However, little else is known about fat storage mechanisms or energy balance regulation.
A greater understanding of genes involved in regulating fat storage in an organism will provide new approaches for the treatment of a variety of conditions involving the energy balance and/or nutritional status of a host, such as obesity, obesity related disorders and anorexia.